The Mets could move to a six-man rotation when Johan Santana (shoulder) returns from the disabled list. Santana's 30-day rehab assignment is scheduled to end on August 27, and a lot can change over the course of a month. That being said, no one in the current rotation deserves the boot, meaning Terry Collins could choose to expand the staff if no one pitches their way out of a job between now and the end of August.